Gear pump

ABSTRACT

A gear pump for pumping a fluid while adjustably controlling a gap between gears and end plates of the gear pump housing. The gear gap is controlled by a gear gap adjustment mechanism operably associated with a gear shaft to move the gear and shaft along a longitudinal axis of the shaft. The gear pump can also include a removable and replaceable friction shield to adjust the gap between the gear and the end plate. The gear pump can further include a dynamic shaft seal assembly for adjusting the sealing about the shaft.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part under 35 U.S.C. §120 based upon co-pending U.S. patent application Ser. No. 12/769,702, filed on Apr. 29, 2009. Additionally, this present application claims the benefit of priority of co-pending U.S. patent application Ser. No. 12/769,702, filed on Apr. 29, 2009. The entire disclosure of the prior application is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to pumps used to pump liquids entrained with abrasives, and more particularly, relating to a gear pump including helical gears of an construction which reduces end plate wear, reduces the tendency for contaminated fluids fouling pump shaft bearing assemblies, permits packing seal adjustment to compensate for seal wear, and permits the adjustment of gear gap between meshing gear teeth.

2. Description of the Prior Art

Pumping liquids and fluids, such as oils and distillates produced from oil wells, presents a problem as these fluids frequently contain entrained contaminating materials such as sand, grit and the like. The pumping of such fluids results in the entrained abrasive materials coming into contact with the pump elements, and in particular, the pump surface elements as well as the pump shaft bearings and seals. Consequently, pumps in service for pumping such liquids require frequent maintenance and repair as a result of premature wear and failure after a relatively short period of use. Pumps employing meshing gears are often used to pump such fluids. Such gear pumps typically include single-helical gears that in operation, as a result of contact between the meshed gear teeth, create axial thrust forces along the pump shafts, which causes an increase in end plate wear.

To address these problems, pumps include modular designs to increase the serviceability of the pump and reduce overall pump downtime; include wear plates to take the axial thrust forces along the pump shafts to reduce end plate wear, and include bearing assemblies and seal arrangements that operate to reduce the tendency of contaminated fluid contact with the bearing assemblies.

Another problem encountered is leaking of fluid externally of the pump due to a worn dynamic packing seal that is used to provide a seal between the protruding end of the pump driving shaft and the pump housing or end plate. Heretofore, servicing and replacement of the packing seal required the pump to be shutdown.

Another problem encountered is the formation of area of high pressurized fluid at the end of a pump shaft created during the pump operation. The pressurized fluid creates an axially loading on the pump shaft causing the pump shaft to be urged towards the opposite end resulting in an increase of pump component wear.

Accordingly, there is a need for a pump design used to pump fluids contaminated with abrasives that has an increased service life and an improved serviceability and that overcomes the limitations associated with conventional pump designs heretofore. In this regard, the present invention substantially fulfills this need. In this respect, the gear pump according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provide an apparatus primarily developed for the purpose of pumping fluids contaminated with abrasives that has an increased service life and an improved serviceability.

BRIEF SUMMARY OF THE INVENTION

In view of the foregoing disadvantages inherent in the known types of pumps now present in the prior art, the present invention provides an improved gear pump, and overcomes the above-mentioned disadvantages and drawbacks of the prior art. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new and improved gear pump and method which has all the advantages of the prior art mentioned heretofore and many novel features that result in a gear pump which is not anticipated, rendered obvious, suggested, or even implied by the prior art, either alone or in any combination thereof.

To attain this, the present invention essentially comprises a gear pump having a pump housing featuring opposite ends, at least one gear fitted to a shaft, and at least one gear gap adjustment mechanism operably associated with the shaft. The gear gap adjustment mechanism includes a first member attachable to the pump housing, a plug member adjustable received in the first member, and a plug shaft coupled to the shaft. The plug shaft is cooperatively moveable with the plug member. The plug member, the plug shaft and the shaft are moveable along a longitudinal axis of the shaft.

The gear gap adjustment mechanism can further include a pair of bearings moveable with the plug member to longitudinally move the plug shaft and shaft upon rotation of the plug member, while allow the plug shaft to freely rotate in relation to the plug member.

There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated.

The invention may also include a friction shield located between the gear and a first end plate or a second end plate.

The invention may also further include a dynamic shaft seal assembly attachable to the pump housing for sealing a second portion of the shaft. The dynamic shaft seal assembly defines a shaft passage configured to receive the second portion of the shaft therethrough. The dynamic shaft seal assembly includes an internally defined fluid filled chamber about the shaft, at least one sealing disc in the passage and about the shaft, at least one bearing adjacent the sealing disc and about the shaft, and a packing nut engageable with an end of the dynamic shaft seal assembly. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims attached.

Numerous objects, features and advantages of the present invention will be readily apparent to those of ordinary skill in the art upon a reading of the following detailed description of presently preferred, but nonetheless illustrative, embodiments of the present invention when taken in conjunction with the accompanying drawings. In this respect, before explaining the current embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of descriptions and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.

It is therefore an object of the present invention to provide a new and improved gear pump that has all of the advantages of the prior art pumps and none of the disadvantages.

It is another object of the present invention to provide a new and improved gear pump that may be easily and efficiently manufactured and marketed.

An even further object of the present invention is to provide a new and improved gear pump that has a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such gear pump economically available to the buying public.

Still another object of the present invention is to provide a new gear pump that provides in the apparatuses and methods of the prior art some of the advantages thereof, while simultaneously overcoming some of the disadvantages normally associated therewith.

Even still another object of the present invention is to provide a gear pump for controlling the gap between gears and a gear and a pump housing end plate. This allows for incremental adjustment between the gears and housing so as to reduce wear and improve pump efficiency.

These together with other objects of the invention, along with the various features of novelty that characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:

FIG. 1 is perspective view of a gear pump constructed in accordance with the principles of the present invention show assembled;

FIG. 2 is a top view of the gear pump schematically illustrating a pressure relieving system;

FIG. 3 is a cross sectional view of the gear pump taken along line 3-3 in FIG. 2;

FIG. 4 is an exploded view of the gear schematically illustrating components of the gear pump;

FIGS. 5A-5C schematically illustrate embodiments of floating dynamic seals receivable in gear end seal mounts;

FIG. 6 is an enlarged schematic view of the gear pump seal neck;

FIG. 7 is an enlarged schematic, cross-sectional view of the gear pump seal neck taken along line 7-7 in FIG. 6, and illustrating an adjustable pump shaft packing seal;

FIG. 8 is an enlarged schematic, cross-sectional view of the seal neck taken along line 8-8 in FIG. 6, and illustrating a lock assembly of the packing nut;

FIG. 9 is an exploded, schematic perspective view of the seal neck, packing nut and packing nut lock assembly;

FIG. 10 is a schematic view of a fluid pressure relief system of the gear pump;

FIG. 11 is perspective view of a modified end plate and schematically illustrating the fluid pressure relieving system;

FIG. 12 is an enlarge, partial cross-sectional view of a gear gap adjustment mechanism of the gear pump;

FIG. 13 is an enlarged side elevation view of a threaded plug of the gear gap adjustment mechanism;

FIG. 14 is an enlarged end view of the threaded plug;

FIG. 15 is an enlarged cross-sectional view of the threaded plug taken along line 15-15 in FIG. 14;

FIG. 16 is a schematic cross-sectional view of the gear pump including heat exchange features;

FIG. 17 is a schematic view of a fluid medium heat exchange feature;

FIG. 18 is a top view of the gear pump including an alternate embodiment gap controller and dynamic driving shaft seal assembly.

FIG. 19 is a cross-sectional view of the gear pump taken along line 19-19 in FIG. 18.

FIG. 20 is an enlarged partial cross-sectional view of the alternate embodiment gap controller of the gear pump.

FIG. 21 is a cross-sectional view of the alternate embodiment gap controller taken along line 21-21 in FIG. 20.

FIG. 22 is an exploded perspective view of the friction shield of the gear pump.

FIG. 23 is an enlarged partial cross-sectional view of the dynamic driving shaft seal assembly of the gear pump.

FIG. 24 is a cross-sectional view of the dynamic driving shaft seal assembly of the present invention taken along line 24-24 in FIG. 23.

The same reference numerals refer to the same parts throughout the various figures.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings and particularly to FIGS. 1-24, an embodiment of the gear pump of the present invention is shown and generally designated by the reference numeral 10.

Schematically illustrated in FIGS. 1-4 is a specially designed gear pump 10 for pumping liquids and fluids, such as oils and distillates containing entrained contaminates such as sand, girt and the like. The gear pump 10 is of the external gear pump type having a driving gear and a driven gear which are disposed within a pump cavity of the gear pump which mesh with each other. The two gears rotate to move a fluid caught in their tooth spaces from a suction side toward a discharge side, thereby performing a pumping action.

Gear pump 10 includes a pump housing 12 having opposite open ends 14, 15 and a sidewall 16 extending therebetween. Sidewall 16 forms a pump cavity 18 and includes opposing suction/discharge ports 20 and 22 extending through the sidewall and into the pump cavity. A pair of end plates 24, 26 is sealingly attached to ends 14, 15, respectively, and seals the pump cavity 18. Each end plate 24, 26 includes a plurality of peripherally disposed fastener mounts such as bolt holes 28 which are used to fasten the end plate to the pump housing 12 by bolts 30.

A pair of meshing gears 32 and 34 is disposed within the pump cavity 18 and extends between end plates 24, 26. Gear 32 is supported by pump shaft 36 which is the pump driving shaft. Gear 34 is supported by idler shaft 38 which is the pump idler shaft. The gears 32, 34 are fixedly secured to driving shaft 36 and idler shaft 38, respectively, for conjoined rotation therewith. To eliminate undesirable play between the gear and shaft, and undesirable meshing between gears 32, 34 during high torque startup, the conventional key and keyway coupling between shaft and gear is replaced by shrink fitting gears 32, 34 to the driving shaft 36 and idler shaft 38, respectively. In this manner, gear 32 and driving shaft 36 become a unitary assembly, and gear 34 and idler shaft 38 become a unitary assembly. The unitary gear/shaft assemblies eliminates vibration between the gear and shaft which serves to reduce pump noise, increase life expectancy of the gears, and to reduce cavity phenomena.

Gears 32, 34 are double-helical gears. The use of double-helical gears eliminates the problem of axial thrust on the pump shafts 36, 38 that is presented by “single” helical gears by having two sets of teeth that are set in a V shape. Each gear in a double helical gear can be thought of as two standard mirror image helical gears stacked. This cancels out the thrust since each half of the gear thrusts in the opposite direction. In this manner the use of wear plates employed to prevent end plate wear in gear pumps is eliminated, and thus reduces the cost of manufacture and maintenance of the gear pump.

Still referring to FIGS. 1-4, end plates 24, 26 are of a similar construction and each include an inward facing side 40 and an opposed outward facing side 42. In some aspects, end plates 24 and 26 are interchangeable, and can be mounted on either ends 14, 15 of pump housing 12. Outward facing side 42 includes a pair of bearing cups or mounts 44, 46 extending outwardly therefrom. First and second shaft passages 48, 50 extend through end plate 24, 26 from the inward facing side 40 through bearing cups 44, 46, respectively, to the outward facing side 42. Bearing cup caps 52A, 52C are sealing attached to the outward facing side of end plate 24 and seal bearing cups 44, 46, respectively. Bearing cup cap 52D is sealing attached to the outward facing side of end plate 28 and seals bearing cup 46. A packing neck 54 is sealing attached to the outward facing side 42 of end plate 28 and seals bearing cup 44. Bearing cup caps 52A, 52B and 52C can be fitted with grease zerk fittings to permit greasing of the shaft bearing assemblies positioned therein.

Referring to FIGS. 3 and 4, end plate 24 includes seal disc mounts 58A and 58C on the inward facing side 40 thereof and coaxial with shaft passages 48 and 50, respectively. Likewise, end plate 26 includes seal disc mounts 58B and 58D on the inward facing side 40 thereof and coaxial with shaft passages 48 and 50, respectively. Seal discs 60A, 60B, 60C, and 60D are mounted to seal disc mounts 58A, 58B, 58C, and 58D, respectively, and cover the inward facing opening of the bearing cups 44, 46 of each end plate 24, 26. In embodiments, seal disc mounts 58A, 58B, 58C, and 58D are each a recess formed on the inward facing side 40 of end plates 24 and 26, respectively, into which seal discs 60A, 60B, 60C, and 60D are received. Seal discs 60A, 60B, 60C, and 60D may be fastened to end plates 24 and 26, respectively by threaded fasteners. In embodiments, seal discs 60A, 60B, 60C, and 60D are flush with the inward facing side 40 of end plates 24 and 26, respectively. Seal discs 60A, 60B, 60C, and 60D may also be referred to as pressure washers as they each taking loading forces from gear end seals, as further described below.

Still referring to FIGS. 3 and 4, end 62 of the driving shaft 36 extends through seal disc 64A and into shaft passage 48 of end plate 24 and is supported for rotation by bearing assembly 64A disposed in bearing cup 44. Bearing assembly 64A includes a bushing 66A which supports end 62 for rotation and a pair of end seals 68A and 70A that are disposed within recesses formed in opposing ends of bushing 66A. End seals 68A and 70A provide sealing contact between the driving shaft 36 and bushing 64A. Further, end seal 68A provides a sealing contact between the bearing cup facing side of seal disc 58A and bushing 66A.

The opposite end 72 of driving shaft 36 extends through seal disc 64C, shaft passage 48 of end plate 26 and through packing neck 54. End 72 is supported for rotation by bearing assembly 64C disposed in bearing cup 44. Bearing assembly 64C includes a bushing 66C which supports end 72 for rotation and a pair of end seals 68C and 70C that are disposed within recesses formed in opposing ends of bushing 66C. End seals 68C and 70C provide sealing contact between the driving shaft 36 and bushing 66C. Further, end seal 68C provides a sealing contact between the bearing cup facing side of seal disc 58C and bushing 66C.

Likewise, end 74 of idler shaft 38 extends through seal disc 58B and into shaft passage 50 of end plate 24, and is supported for rotation by bearing assembly 64B disposed in bearing cup 46. Bearing assembly 64B includes a bushing 66B which supports end 74 for rotation and a pair of end seals 68B and 70B that are disposed within recesses formed in opposing ends of bushing 66B. End seals 68B and 70B provide sealing contact between the idler shaft 38 and bushing 66B. Further, end seal 68B provides a sealing contact between the bearing cup facing side of seal disc 58B and bushing 66B

The opposite end 76 of idler shaft 38 extends through seal disc 58D and into shaft passage 50 of end plate 26, and is supported for rotation by bearing assembly 64D disposed in bearing cup 48. Bearing assembly 64D includes a bushing 66D which supports end 76 for rotation and a pair of end seals 68D and 70D that are disposed within recesses formed in opposing ends of bushing 66D. End seals 68D and 70D provide sealing contact between the idler shaft 38 and bushing 66D. Further, end seal 68D provides a sealing contact between the bearing cup facing side of seal disc 58D and bushing 66D.

Still referring to FIGS. 3 and 4, gear end seal 78A is disposed about driving shaft 36 and between the inward facing side of seal disc 58A and end 80 of gear 32. Gear end seal 78A provides a sealing contact between end 80 of gear 32 and the inward facing side of seal disc 58A. Gear end seal 78A is mounted to gear end mount 82A on end 80 of gear 32. Gear end seal 78C is disposed about driving shaft 36 and between the inward facing side of seal disc 58C and end 84 of gear 32. Gear end seal 78C provides a sealing contact between end 84 of gear 32 and the inward facing side of seal disc 58C. Gear end mounts 82A and 82C are recesses in ends 80 and 84, respectively which gear end seals 78A and 78C are disposed.

Gear end seal 78B is disposed about idler shaft 38 and between the inward facing side of seal disc 58C and end 86 of gear 34. Gear end seal 78B provides a sealing contact between end 86 of gear 34 and the inward facing side of seal disc 58B. Gear end seal 78B is mounted to gear end mount 82B on end 88 of gear 34. Gear end seal 78D is disposed about idler shaft 38 and between the inward facing side of seal disc 58D and end 88 of gear 34. Gear end seal 78D provides a sealing contact between end 88 of gear 34 and the inward facing side of seal disc 58D. Gear end mounts 82B and 82D are recesses in ends 86 and 88, respectively which gear end seals 78B and 78D are disposed. In embodiments, gear end seals 78A, 78B, 78C and 78D are floating seals. However, it is contemplated the floating seals could be replaced with non-floating seals and provide a sealing contact as intended.

Fluids from the pump cavity 18 are kept from contact with bearing assembly 64A by means of end seal 68A, seal disc 58A and gear end seal 78A, from bearing assembly 64B by means of end seal 68B, seal disc 58B and gear end seal 78B, from bearing assembly 64C by means of end seal 68C, seal disc 58C and gear end seal 78C, and from bearing assembly 64D by means of end seal 68D, seal disc 58D and gear end seal 78D. To this end, debris entrained in the pumped fluid are prevented from contact with bearing assemblies 64A, 64B, 64C and 64D, and thus extending the service life thereof.

With reference to FIGS. 5A, 5B and 5C, a plurality of embodiments of gear end seals 78A-78D are shown. In FIG. 5A, there is shown an elastic frontal labyrinth seal. In FIG. 5B, there is shown a frontal labyrinth seal with O-ring as elastic element. In FIG. 5C, there is shown a frontal labyrinth seal with wave spring as elastic element.

Schematically depicted in FIGS. 6-9, is gear pump 10 having an adjustable driving shaft packing seal assembly 100. Packing seals are conventional used to prevent fluid that is being pumped from leaking through the exposed interface between the protruding pump shaft and the pump housing. As the packing seal becomes worn, the seal begins to fail and leak. Heretofore, the only solution to a worn, leaking packing seal is to shutdown the pump to allow the disassembly and the replacement of the worn packing seal components. The assembly 100, embodied herein, permits an operator to adjust the packing seal as it becomes worn in order to extend the service life of the packing seal without requiring the pump to be shutdown.

Seal neck 54 comprises a body 102 having opposed ends 104 and 106, and a longitudinal shaft passage 108 extending through ends 104 and 106. End 104 is adapted to be mounted to bearing cup 44 with driving shaft 36 extending through shaft passage 108 and beyond end 106 with end 72 protruding externally to permit operable coupling of the driving shaft to a source of rotational power, such as an engine or motor. A pair of bushings 111 and 112 are disposed within shaft passage 108 about driving shaft 36 and provide rotational support to the driving shaft. A packing seal 114, such as a Teflon rope, is interdisposed between bushings 111 and 112 about drive shaft 36, and provides a seal interface between driving shaft 36 and shaft passage 108. A packing nut 110 is threaded onto end 106 of seal neck 54 with driving shaft 36 extending through shaft bore 116.

Bushing 111 is disposed in shaft passage 102 with end 118 thereof abutting against shoulder surface 120 of shaft passage 102 and with the opposite end 122 engaged with end 124 the packing seal 114. End 124 may be inwardly chamfered to provide a seat into which end 124 of the packing seal is received. Busing 112 is disposed in shaft passage 102 with end 126 thereof extending beyond end 106 of seal neck 54 and engaged with surface 128 of the pack nut 110. The opposite end 130 of bushing 112 is engaged with end 132 of packing seal 114. End 130 may be inwardly chamfered to provide a seat into which end 132 of the packing seal 114 is received. Threading packing nut 110 onto seal neck 54 causes bushings 111 and 112 to compress packing seal 114 between ends 118 and 130 of bushings 111 and 112, respectively, and creates a sealing contact between driving shaft 36 and shaft passage 108.

The assembly 100 further includes a packing nut lock 140 that operates to either preclude the turning of packing nut 110 when moved into one position or to permit the turning of packing nut when moved into another position. As best seen in FIGS. 7 and 8, the packing nut lock 140 includes a collar 142 fitted about packing nut body 144. Collar 142 is secured to body 144 for axial rotation about packing nut body by a pair of pins 146 and 148 that are inserted through holes 150 and 152, respectively, of collar 142 and at least partially into slots 154 and 156, respectively, of packing nut body 144, as best seen in FIG. 8. In this manner, the collar 142 is limited to a few degrees of rotation about packing nut body 144 between a first position and a second position. The assembly of collar 142 with packing nut body 144 captivity retains a pair of check balls 158 and 160 in holes 162 and 164, respectively, of the packing nut body 144 by the inner surface 146 of the collar. A plurality of flat lands 170 is circumferentially located on the exterior surface of the seal neck 54.

When collar 142 is rotated into the first or ON position, as shown in FIG. 8, cavities 166 and 168, formed on the interior surface of collar 142, are registered with holes 162 and 164. This registration permits check ball 158 to be partially received by cavity 166 and check ball 160 to be partially received by cavity 168. In this manner, packing nut 110 is permitted to be rotated about seal neck 54 with check balls 158 and 160 floating over lands 170. When collar 142 is rotated into the second or OFF position, cavities 166 and 168 are moved out of registration with holes 162 and 164, and the inner surface 146 presses check balls 158 and 160 against a flat land 170, as shown in FIG. 8 in dashed line. In this manner, packing nut 110 is precluded from rotating about seal neck 54, and therefore, is locked.

In operation, as packing seal 118 becomes worn and leaks, an operator may further compress the packing seal 118 to tighten the seal between the shaft passage 108 and the driving shaft 36 to preclude the leaking without shutting down the operation of the pump. The packing seal 118 is further compressed by rotating collar 142 into the ON position and then rotating the packing nut 110 further onto the seal neck 54. Once fluid stops leaking, collar 142 is rotated into the OFF position, thereby locking the threaded position of the packing nut 110 on the seal neck.

Schematically depicted in FIGS. 2 and 10, is gear pump 10 having pressure relief system to vent fluid pressure that may occur at end 62 of driving shaft 36 to prevent axial forces along driving shaft and avoiding end plate wear. The pressure relief system includes first and second fluid passages 200 and 202, each in fluid communication with fluid located at end 62 of the driving shaft 36. The first passage 200 is further in fluid communication with suction/discharge port 20, and the second passage 202 is further in fluid communication with suction/discharge port 22. A check valve 206 and needle valve 208 are positioned across the first passage 200 and a check valve 210 and needle valve 212 are positioned across the second passage 202. Check valves 206 and 210 operate to permit fluid to follow through passages 200 and 202, respectively, only in the direction towards suction/discharge ports 20 and 22. Needle valves 208 and 212 are each adjusted to permit fluid flow through passages 200 and 202, respectively, when fluid at end 62 of the driving shaft 36 is at a threshold pressure. In FIG. 11, end plate 24 is schematically depicted including ports 214 and 216 for connection with fluid passages 200 and 202 with suction/discharge ports 20 and 22, respectively. Needle valves 208 and 212 are optional. Additionally, while the pressure relief system is illustrated and described with reference only to end 62 of driving shaft 36, the pressure relief system can be employed to release pressure at the ends of any of the pump shafts.

Schematically depicted in FIGS. 12-15, is gear pump 10 having a gear gap control mechanism 300 to adjust the meshing of gears 32 and 34 by axially displacing driving shaft 36. In this embodiment, bearing cup cap 52A is replaced by bearing cup cap 52A′ and end 62 of driving shaft 36 has been milled to include axial bore 302. Mechanism 300 further includes a plug member 304 threadably received by bore 306 that extends through end plate 24 along longitudinal axis 307 of driving shaft 36. Inward end 308 of plug 304 includes bore 310 into which is disposed is cup member 312. Ball 314 is interdisposed between end 62 of the driving shaft 36 and cup member 312, and is partially seated within cup member 312 and axial bore 302. Ball 314 provides a dynamic bearing interface between cup member 312 and end 62 of the driving shaft 36. Threading plug 304 into bore 306 causes ball 314 to urge against end 62 of the driving shaft 36. Further threading of plug 304 into bore 306 results in a longitudinal displacement of driving shaft 36 along axis 306, and thus moves the longitudinal position of gear 32 relative to the longitudinal position of gear 34. The threaded position of plug 304 can be adjusted to control relative longitudinal positions of gears 32 and 34, and thus the gap between the gear teeth. The threaded position of plug 304 can be locked in place by a screw or threaded pin 316 threadably received within bore 318 that extends normal to bore 306. Threading pin 316 into bore 318 caused end 320 of the pin to be received by one of a plurality of circumferentially spaced and longitudinally extending grooves 322 on the exterior of plug barrel 324, and thus locking plug 304 from rotation within bore 306. An O-ring seal 326 can provide a sealing interface between bore 306 and plug 304. Additionally, while the gap control is illustrated and described with reference only to end 62 of driving shaft 36, the gap control can be employed at the ends of any of the pump shafts.

Schematically depicted in FIGS. 16 and 17, is gear pump 10 having one or more heat exchange features to either cool the gear pump in hot climates or heat the gear pump in cold climates. In one aspect, a heat exchanger body 402 is mounted to the exterior of the pump housing 12, for example by welding. One or more electric heating elements 404 are disposed within body 402 that are operably connected to a source of electrical power (not shown) by leads 405. When operating, electric heating elements 404 output radiant heat that is transmitted into the pump casing 12 and heating the components of the gear pump 10 to prevent lockup due operating in cold climates. In another aspect, a heat exchanger body 406 is mounted to the exterior of the pump housing 12, for example by welding. Body 406 include an internal serpentine fluid flow passage 407 extending between inlet and out let ports 408 and 410. Ports 408 and 410 are fitted with couplings 412 that permit the flow passage 407 to be fluidically connected to an engine cooling system (not shown) to receive the flow of antifreeze or other heat exchanging fluid medium 414 from the engine cooling system. The flow of fluid through flow passage 407 heats or cools the pump housing 12 and thus the pump components to prevent lockup due to freezing weather or from overheating.

Schematically depicted in FIGS. 18-24, is an alternate embodiment gear gap controller 420 and dynamic driving shaft seal assembly 600 associated with gear pump 10. Gear pump 10 includes a pump housing 12, and a pair of end plates 24, 26. The housing 12 includes opposite open ends 14, 15 and a sidewall 16 extending therebetween. Sidewall 16 forms a pump cavity 18 and includes opposing suction/discharge ports 20 and 22 extending through the sidewall and into the pump cavity. The pair of end plates 24, 26 is sealingly attached to ends respectively, and seals the pump cavity 18. Each end plate 24, 26 includes a plurality of peripherally disposed fastener mounts such as bolt holes which are used to fasten the end plate to the pump housing 12 by bolts or fasteners.

The gears 32, 34 are fixedly secured to driving shaft 36 and idler shaft 38, respectively, for conjoined rotation therewith. To eliminate undesirable play between the gear and shaft, and undesirable meshing between gears 32, 34 during high torque startup, the conventional key and keyway coupling between shaft and gear is replaced by shrink fitting gears 32, 34 to the driving shaft 36 and idler shaft 38, respectively. In this manner, gear 32 and driving shaft 36 become a unitary assembly, and gear 34 and idler shaft 38 become a unitary assembly. Gears 32, 34 can be double-helical gears, V-shaped helical gears, or any known type of helical gears that can mesh with each other.

The driving shaft 36 extends through seal disc 64A and into shaft passage of end plate 24 and is supported for rotation by bearing assembly 64A. Bearing assembly 64A includes a bushing or bearing 66A which supports end 62 of driver shaft 36 for rotation, and a pair of end seals 70A. End seals 70A provide sealing contact between the driving shaft 36 and bushing 66A.

FIG. 19 is shown with helical gears “V” shape installed, but it can be appreciated that other gears can be used. Due to the angle of the helical gears teeth, an axial force is always present; either the drive shaft 36 is rotated clock wise or counter clock wise. Therefore, with no special means, while rotating, the gears 32, 34 will over wear the inner surfaces of the end plates 24, 26 as well as their lateral surfaces shortening drastically the duration in operations. As such, an initial gap G between the gears 32, 34 and their respective end plates 24, 26, will increase and premature loss in suction and loss in fluid flow is noticed.

The gap control mechanism 420, as best illustrated in FIGS. 20 and 21, can be associated with at least one of the end plates 24, 26 to control the gap G by axially displacing driving shaft 36 or idler shaft 38, respectively, which in turn adjusts the meshing of gears 32 and 34. The gap controller 420 can keep both gears 32, 34 in the “center” or to maintain the same gap G on each side of the gears. In this embodiment, the gap controller 420 includes an inner bushing 422, a plug member 450, a plug shaft 460, and a bearing cup cap 480. The end plates 24, 26 have been milled to include a bore along a longitudinal axis 307 of driving shaft 36, which is configured to receive a portion of an inner bushing 422. Additionally, end 62 of driving shaft 36 has been milled to include axial bore 302 and recess 303 to receive a portion of a plug shaft 460.

The inner bushing 422 includes a bushing bore 427 defined therethrough along longitudinal axis 307, and a flange 424 that can be secured to the end plates 24, 26 via a fastener 442 passing through the flange 424 and engaged with a bore defined in the end plates 24, 26. An inward end 426 of the inner bushing 422 is received in a bore defined through the end plates 24, 26, and can be sealed thereagainst by way of a sealing ring. The bushing bore 427 can include a threaded section, and varying radial extensions to produced ledges along the length of the bushing bore 427.

The plug member 450 is threadably received in the bushing bore 427 of the inner bushing 422. The plug member 450 includes a bore defined therethrough along longitudinal axis 307, an inward end 452 received in the bushing bore 427, an outward end 454 having a flange adapted to contact an outward end 428 of the inner bushing 422, a thread section 458 between the inward and outward ends 452, 454, and a concentric plug ledge 456 inwardly extending into the plug member bore. The thread section 458 is engageable with a thread section of the inner bushing 422 associated with the bushing bore 427.

The plug shaft 460 includes an inward end 462 that is threadable received in the shaft bore 302, an outward end 470, and an outwardly extending plug shaft ledge 466 between the inward and outward ends 462, 470. A flared section 464 of the inward end 462 adjacent the plug shaft ledge 466 has a diameter greater than that of the inward end 462, and is received in an recess 303 defined in the end of the shaft 36. The recess 303 is in communication with the bore 302. The outward end 470 extends through an opening defined by the plug ledge 456.

A nut 472, such as but not limited to a Nylock flanged threaded nut, is threadably engaged with a threaded section of the outward end 470, and which abuts against an edge of the plug shaft 460. A lock ring 474 can be used to prevent the nut 472 from being accidentally removed from the outward end 470.

A first thrust ball bearing 492 is located between the plug ledge 456 and the plug shaft ledge 466, while a second thrust ball bearing 494 is located between the plug ledge 456 and the nut 472. The bearings 492, 494 are adapted to receive the outward end 470 therethrough, so as to allow the plug shaft 460 to rotate freely in relation to the plug member 450. The first and second bearings 492, 494 are positioned against the plug ledge 456 so that their inside faces or surfaces are facing each other.

The bearing cup cap 480 includes an opened inward end 482, a closed outward end 488, an outwardly extending cap ledge 486 located between the inward and outward ends 482, 488, and an interior cavity 484. The inward end 482 is sealably received in the longitudinal bore of the plug member 450 so as to be adjacent the second bearing 494. The cap ledge 486 is received in an annular notch defined in the outward end 454 in communication with the bore of the plug member 450. The cap ledge 486 prevents the bearing cup cap 480 from being inserted completely into the plug member 450. The interior cavity 484 is configured to receive at least the plug shaft outward end 470 and the nut 472. A retaining ring 490 can be used to removably secure the bearing cup cap 480 in the plug member 450.

The plug member 450, plug shaft 460, bearings 492, 494 and bearing cap cup 480 provides a dynamic bearing interface between inner busing 422 and end 62 of the driving shaft 36. Threading plug member 450 into bushing bore 427 causes plug ledge 456 to urge against first bearing 492 which urges against plug shaft ledge 466 thus moving the plug shaft 460. Further threading of plug member 450 into bushing bore 427 results in a longitudinal displacement of driving shaft 36 along axis 306 via plug shaft 460, and thus moves the longitudinal position of gear 32, 34 relative to the longitudinal position of gear 32, 34, respectively.

Threading plug member 450 out of bushing bore 427 causes plug ledge 456 to urge against second bearing 494 which urges against nut 472 thus moving the plug shaft 460. Further threading of plug member 450 out of bushing bore 427 results in a longitudinal displacement of driving shaft 36 along axis 306 via plug shaft 460, and thus moves the longitudinal position of gear 32, 34 relative to the longitudinal position of gear 32, 34, respectively. The threaded position of plug member 450 can be adjusted to control relative longitudinal positions of gears 32 and 34, and thus the gap between the gear teeth and/or the gap G.

The threaded position of plug member 450 can be locked in place by a screw or threaded pin 440 threadably received within bore 438 of the inner bushing 422 that extends normal to bushing bore 427. An end of the threading pin 440 can be received by one of a plurality of circumferentially spaced and longitudinally extending grooves on the exterior of plug member 450, and thus locking the plug member 450 from rotation within bushing bore 427.

Furthermore, alone or in combination with threaded pin 440, a second fastener 434 including a rubber cord 436 received within flange bore 432 through the flange 424 of the inner bushing 422 that extends normal to bushing bore 427 can be used lock the plug member 450 in place.

Additionally, while the gap control is illustrated and described with reference only to end 62 of driving shaft 36, the gap control can be employed to at the ends of any of the pump shafts.

With the nut 472, bearing cup cap 480 and retaining ring 490 removed, the plug member 450 can be screwed in to the maxim. The gears 32, 34 are moved from left to right until the gap G is at a predetermined distance. Screwing nut 472 on the plug shaft 460 adjust the clearance; gears inner end plate and inside of the first and second bearings 492, 494 becomes zero “0”. In order to allow a film of oil for lubricating the first and second bearings 492, 494, a predetermined clearance is to be assured.

In order to set the gear equally spaced (same gap on each side) the full pack of shrank gear must be moved from right to left with a gap distance G. After this setting is done, the bearing cup cap 480 and retaining ring 490 are to be installed. After which, the threaded pin 440, and second fastener 434 with rubber cord 436 are to be tightened up and locked with Loctite.

The gap controller mechanism 420 solves the very well-known problem produced by helical gears (either standard or “V” shape teeth gear) in, that eliminates the axial force by using an external means.

As best illustrated in FIG. 22, the friction shield 500 is mounted to a shield mount 58A′, and covers the inward facing opening of the end plates 24, 26. The friction shield 500 includes a pair of planar bodies 502 that are shaped similar to that of the ends of the gears 32, 34. The friction shield 500 also defines a plurality of notches 506 to receive fastening bolts associated with the end plates 24, 26, and bores 504 to receive the driver shaft 36 and idler shaft 38, respectively. In embodiments, shield mount 58A′ is a recess formed on the inward facing side of end plates 24 and 26, respectively, into which one or more friction shields 500 are received. Friction shield 500 may be fastened to end plates 24 and 26 or to additional friction shields, respectively by threaded fasteners 508. In embodiments, friction shield 500 is flush with the inward facing side of end plates 24 and 26, respectively.

In other embodiments, a shim 510 can be positioned between the end plates 24, 26 and the friction shield 500, thereby extending a face of the friction shield 500 into the gap G so as to adjust the size of the gap G and thus adjusting the surface wearing on the gear end. The shim 510 can have a shape corresponding to that of the friction shield 500, and can be secured thereto by fasteners 508.

Referring to FIGS. 23 and 24, the adjustable driving shaft packing seal assembly 600 is configured to prevent fluid that is being pumped from leaking through the exposed interface between the protruding driver shaft 36 and the pump housing 12. As the packing seal becomes worn, the seal begins to fail and leak. The seal assembly 600, embodied herein, permits an operator to adjust the packing seal as it becomes worn in order to extend the service life of the packing seal without requiring the pump to be shutdown. The seal assembly 600 acts like a dynamic seal system on the driver shaft 36.

Seal neck body 602 has an inward flanged end 604, an outward threaded end 606, and a longitudinal shaft passage 608 extending through ends 604 and 606. Inward end 604 is adapted to be mounted to end plate 26 with driving shaft 36 extending through shaft passage 608 and beyond outward end 606 with end 72 protruding externally to permit operable coupling of the driving shaft 36 to a source of rotational power, such as an engine or motor. A first pair of a cage roller 614A and double inner lip dynamic seals 616A is positioned in the end plate 26 and receives the driver shaft 36 therethrough. The cage rollers 614A, 614B can be, but not limited to, a needle bearing without an inner roller.

Interior of the shaft passage 608 is a second pair cage roller 614B and double inner lip dynamic seals 616B separated by an intermediate grease filled chamber 610. The grease in the chamber 610 surrounds the driver shaft 36. A washer 612 closes and seals the chamber 610, and is adjacent the second cage rollers 614B and dynamic seals 616B. A snap ring 618 secures the first pack of cage rollers 614A and dynamic seals 616A, and washer 612 in positioned. A bushing or Teflon rope coil 620 is position about the driver shaft 36 adjacent the snap ring 618. A bushing 622 is positioned adjacent the rope coil 620 and extends between outward end 606. The cage rollers 614A, 614B, dynamic seals 616A, 616B and rope coils 620 can be filled with grease.

A packing nut 630 is threaded received on the threaded outward end 606 of the neck body 602. The packing nut 630 includes a bore 632 through an outward end that receives the driver shaft 36 therethrough, a threaded section 634, and a flanged outward end 636. The internal threaded section 634 is configured to engage with the treaded outward end 606 of the neck body 602. The flanged inward end 636 is configured to receive therethrough the outward end 606.

Threading packing nut 630 onto seal neck body 602 causes bushing 622 to compress rope coil 620 against snap ring 618, and creates a sealing contact between driving shaft 36 and shaft passage 608. Further threading of packing nut 630, increases the compression on rope coil 620, thus increasing the sealing contact on driving shaft 36.

The threaded position of packing nut 630 can be locked in place by a fastener, screw or threaded pin 642 threadably received within bore 640 of the packing nut 630 that extends normal to shaft passage 608. An end of the threading fastener 642 can be received by one of a plurality of circumferentially spaced and longitudinally extending grooves or flat lands 603 on the exterior of the neck body 602, and thus locking packing nut 630 from rotation, as best illustrated in FIG. 24. In this manner, the packing nut 630 is limited to a few degrees of rotation about the outward end 606 of the neck body 602 between multiple positions. The grooves 603 allow an incremental tightening of the rope seal 620 by means of the precision height fastener 642 and any spring washer associated therewith.

The gear pump 10 works as an atypical hydraulic gear pump as the working fluid in most cases is an unfiltered fluid, such as but not limited to crude oil, mud, slurries or unfiltered water. Thus, the first double inner lip dynamic seals 616A are always exposed to tinny hard particles and noticed over long field experiments of having a relatively short life expectancy.

In order to increase the pump's duration in exploitation, the chamber 610 has been machined and filled with light grease. Additionally, the second double inner lip dynamic seal 616B and cage roller 614B keeps the grease inside the chamber 610.

While in operation the gear pump 10 (pumping either one direction or the other one) produces a static pressure P1 which is always noticed at the first lip of the first dynamic seal 616A. A smaller pressure P2 is also noticed at the entrance of the second double inner lip dynamic seal 616B, as represented by ΔP in FIG. 24. It can be appreciated that until first hard particles penetrate through the first inner lips of the first dynamic seal 616A, the second seal 616B works continuously with clean grease from the chamber 610, with less frontal static pressure and therefore any wear on the second seal 616B is insignificant. Once the first hard particles penetrate the first two lips 616A, the contaminated leakage will combine with the existing clean grease in chamber 610 and, after a while will start affecting the second double inner lip dynamic seal 616B.

In operation field reports have showed that the dynamic seal system 600 has increased the working or life duration of more than 200%, which is a substantial advantage over the prior art.

While embodiments of the gear pump have been described in detail, it should be apparent that modifications and variations thereto are possible, all of which fall within the true spirit and scope of the invention. With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. And although gear pumps have been described, it should be appreciated that the gap controller and dynamic driving shaft seal assembly herein described is also suitable for adjusting the longitudinal distance of an element fitted to a shaft and/or adjustably sealing around any rotating member.

Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. 

What is claimed as being new and desired to be protected by Letters Patent of the United States is as follows:
 1. A gear pump comprising: a pump housing having opposite ends; at least one gear disposed within said pump housing, said gear having opposed and outwardly facing first and second ends, said gear being fitted to a shaft; and at least one gear gap adjustment mechanism operably associated with said shaft, said gear gap adjustment mechanism having a first member attachable to said pump housing, a plug member received in said first member, and a plug shaft coupled to said shaft and cooperatively moveable with said plug member; wherein said plug member, said plug shaft and said shaft being moveable along a longitudinal axis of said shaft.
 2. The gear pump of claim 1, wherein said plug member is rotatably received in said first member via a threaded section, and said plug member includes an inwardly extending plug ledge defining a bore configured to receive a section of said plug shaft therethrough.
 3. The gear pump of claim 2, further comprising a bearing adjacent said plug ledge and a plug shaft ledge of said plug shaft, wherein said bearing is configured to transfer longitudinal movement of said plug member to said plug shaft while allowing said plug shaft to rotate in relation to said plug member.
 4. The gear pump of claim 2, further comprising a bearing adjacent said plug ledge and a nut engaged with an outward end of said plug shaft, wherein said bearing is configured to transfer longitudinal movement of said plug member to said plug shaft while allowing said plug shaft to rotate in relation to said plug member.
 5. The gear pump of claim 1, wherein said plug shaft is threadably received in a bore defined in an end of said shaft.
 6. The gear pump of claim 1, wherein said plug member is releasably locked in position by at least one fastener through said first member.
 7. The gear pump of claim 1, wherein said gear gap adjustment mechanism further comprising a cap sealingly received in said plug member.
 8. The gear pump of claim 1, further comprising first and second end plates sealingly joined to said opposite ends of said pump housing, said first end plate having a first end plate shaft passage to receive a first portion of said shaft therethrough and a first mount on an inner side of said first end plate coaxial with said first end plate shaft passage, said second end plate having a second end plate shaft passage to receive a second portion of said shaft therethrough and a second mount on an inner side of said second end plate coaxial with said second end plate shaft passage.
 9. The gear pump of claim 8, further comprising a friction shield received in one of said first mount and said second mount, said friction shield is a removable plate secured to one of said first end plate and said second end plate respectively.
 10. The gear pump of claim 9, wherein said first end plate includes a bearing adjacent a sealing disc, said bearing and sealing disc being located in said first end plate shaft passage between said friction shield and said first member, said bearing and sealing disc being configured to receive said first portion of said shaft therethrough.
 11. The gear pump of claim 9, further comprising at least one shim positioned between said friction shield and one of said first end plate and said second end plate respectively, said shim is configured to adjust a gap between said friction shield and one of said first and second ends of said gear respectively.
 12. The gear pump of claim 8, further comprising a dynamic shaft seal assembly attachable to said second end plate, said dynamic shaft seal assembly defining a shaft passage configured to receive a second portion of said shaft therethrough, said dynamic shaft seal assembly comprising an internally defined chamber about said shaft, at least one sealing disc in said passage and about said shaft, at least one bearing adjacent said sealing disc and about said shaft, and a packing nut engageable with an end of said dynamic shaft seal assembly.
 13. The gear pump of claim 12, wherein said dynamic shaft seal assembly further comprising a ring adjacent said chamber and said sealing disc, said ring contacts a ledge formed in said shaft passage to retain grease in said chamber.
 14. The gear pump of claim 12, wherein said dynamic shaft seal assembly further comprising a coiled sealing element about said shaft and compressible by rotation of said packing nut.
 15. The gear pump of claim 14, wherein said dynamic shaft seal assembly further comprising a bushing adjacent said coiled sealing element and said packing nut, said bushing being configured to transfer compression to said coiled sealing element from rotation of said packing nut.
 16. The gear pump of claim 12, wherein said second end plate further comprising a sealing disc and a bearing in said second end plate shaft passage and adjacent said dynamic shaft seal assembly.
 17. The gear pump of claim 1, wherein said gear pump includes a first fluid port and a second fluid port configured to allow passage of a fluid pumped by said gear.
 18. The gear pump of claim 1, wherein said gear is shrink fitted to said shaft, and said gear is selected from the group consisting of double-helical gears, and V-shaped helical gears. 